The aircraft carrier leading the US military's tsunami relief effort has left Indonesian waters after Indonesia declined to let the ship's fighter pilots use its airspace for training missions.

USS Abraham Lincoln's diversion, which will not affect aid flights, came as the White House asked the Indonesian Government to explain why it appeared to be demanding the US military and other foreign troops providing disaster relief leave the country by the end of March.

"We'll seek further clarification from Indonesia about what this means," said Scott McClellan, the White House press secretary. "We hope that the Government of Indonesia and the military in Indonesia will continue the strong support they have provided to the international relief efforts so far."

Under US Navy rules, pilots of carrier-based warplanes cannot go longer than 14 days without flying, or they have to undergo extensive retraining.

The Indonesian Government said on Wednesday that foreign troops would be out of the country by March 31.

Subsequently US marines have scaled back plans to send hundreds of troops into Indonesia to build roads and clear debris.

After long discussions with the Indonesian Government, the US military called off plans to base the marines on land. Instead, smaller numbers are going ashore by day to help with relief and returning to their vessels in the evening. The marines' primary task is now ferrying humanitarian workers and food from the amphibious assault ship USS Bonhomme Richard.

The Financial Times reported on Monday that a US plan to use navy landing craft to deploy about 1000 marines in Aceh had been delayed because of Indonesian concern that it might resemble an invasion.

Major Rick Steele said the US had planned to deploy the marines at the weekend to help provide water-purification services, reconnect power supplies, restore hospitals, repair roads and rebuild bridges and provide other basic aid. "We're only doing what the Indonesian Government lets us do," he told the Financial Times. "They teach at their military schools here that the way the US takes over countries is by moving in."

Australia's relief effort in Indonesia entered a new phase yesterday with the arrival of HMAS Kanimbla. The amphibious transport ship anchored just off Banda Aceh's ruined port with 400 army engineers on board.